JPH11294965A - Refractory spraying execution method and spraying material used for it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a refractory spraying execution method that has a superior heat insulation property and at the same time can form thick execution body, and a spraying material used for the method. SOLUTION: In a refractory spraying execution method, execution water is added to a spraying material that contains fireproof aggregate, a bonding agent, an organic filament, and a spherical hollow grain involving gas consisting of thermoplastic resin with an average particle diameter of 5-200 μm in advance for supplying to a nozzle 1 by a forced feed pump, a rapid coagulation agent is added into the nozzle 1 for spraying, and the spraying material is used. The spherical hollow grain involving gas disappears, and execution body texture becomes porous, thus showing an insulation property, greatly improving dripping of the spraying material, and effectively forming a thick execution body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refractory spraying method capable of forming a structure having excellent heat insulation and a large thickness, and a spraying material used for the method.

[Prior art]

[0002] In the lining of industrial kilns or repairs thereof, refractory spraying is performed. As this spraying construction method, there has been proposed a method of spraying a spraying material to which a working moisture is added in advance by adding a quick-setting agent in a nozzle (for example, Japanese Patent Application Laid-Open No. 54-61005). In this method, the spray material is supplied to the nozzle by a pressure pump,
A large amount of spraying can be performed at one time compared to the normal spraying work in which the sprayed material is pneumatically fed, and the work efficiency is excellent.

[0003] The main properties required for the spraying material used in this method are adhesion and durability, but recently the demand for heat insulating properties has further increased. The heat insulating property has effects such as energy saving and heat protection of kiln equipment.

[0004] In order to impart heat insulating properties to a conventional spray material, a porous or hollow lightweight refractory aggregate is added. It is also known that heat insulation can be obtained by adding an organic short fiber and forming a porous layer formed by the disappearance of the organic short fiber.

[0005]

However, because of the small specific gravity of the lightweight refractory aggregate, the refractory aggregate is separated from other refractory aggregates during the pressurized feeding in the nozzle or when discharged from the nozzle, and the construction body having a uniform composition is obtained. Can not be obtained. On the other hand, organic short fibers are effective in improving the adhesion of the spray material, but when added in a large amount to obtain a heat insulating effect, they become pills in the spray material, and the workability of the spray material and the uniformity of the structure are reduced. Significantly lowers.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems. The characteristic feature is that a spraying material containing a refractory aggregate, a binder and organic short fibers, and a gas-containing spherical hollow particle made of a thermoplastic resin having an average particle diameter of 5 to 200 μm is added in advance by adding construction moisture. And a refractory spraying method in which a pressurizing pump is supplied to a nozzle and a quick-setting agent is added and sprayed in the nozzle, and a spray material used in this method.

According to the present invention, the spraying material contains gas-containing spherical hollow particles (hereinafter, simply referred to as gas-containing spherical hollow particles) made of a thermoplastic resin, and receives drying heat or furnace residual heat after spraying. The above-mentioned gas-containing spherical hollow particles disappear, and the structure of the construction body is made porous. Then, the construction body structure exhibits heat insulation properties due to the porous structure.

The gas-containing spherical hollow particles used in the present invention have a very small specific gravity, but when pressed in the nozzle or when discharged from the nozzle, other refractory aggregates which have been seen in the conventional material containing a lightweight refractory aggregate are used. Is prevented from being separated. This is because the gas-containing spherical hollow particles are extremely fine and have flexibility due to the gas-containing resin, so that the matrix portion of the spray material structure after the addition of the working water increases as the shear rate increases. It is considered that a so-called pseudoplastic flow in which the viscosity is reduced is caused, and the viscosity becomes a resistance to prevent the gas-containing spherical hollow particles from being separated.

Even with the same fine spherical hollow particles, for example, alumina-siliceous spherical hollow particles do not have the above-described effect of preventing separation because of lack of flexibility. Also, since the gas-containing spherical hollow particles are fine and spherical, there is no decrease in fluidity which is observed when a lightweight refractory aggregate or organic short fiber is added. Furthermore, because of the pseudoplastic flow described above,
ADVANTAGE OF THE INVENTION According to this invention, the dripping after the spraying material adheres is significantly improved, and it is effective in forming a thick construction body.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The specific materials and proportions of the refractory aggregate, binder and organic short fibers of the spraying material used in the present invention are not different from those of the prior art. Refractory aggregates include, for example, alumina, magnesia, spinel, magnesia-calcia, shale, bauxite, mullite, pyrophyllite, pyroxene, chamotte, andalusite, silica, chromite, bauxite, sillimanite, zircon, and the like. For example, zirconia, carbon, silicon carbide, boron carbide, boron titanium, boron zirconium, clay, titania, calcined alumina, silicon nitride, aluminum nitride, volatile silica, and the like are combined as needed. The particle size of the refractory aggregate is adjusted to coarse particles, medium particles, and fine particles as usual in consideration of adhesion, workability, filling property, and the like.

The spraying material used in the present invention has excellent heat insulating properties due to the incorporation of gas-containing spherical hollow particles described later.
As long as the fluidity of the spray material during construction does not significantly decrease,
Part of the refractory aggregate may be replaced by a porous or hollow lightweight refractory aggregate.

Specific examples of these lightweight refractory aggregates include lightweight alumina, lightweight chamotte, perlite, vermiculite, alumina hollow particles, alumina-silica hollow particles, ash balloon, glass balloon and the like. It should be noted that the blending of the lightweight refractory aggregate lowers the flowability of the sprayed material at the time of construction, so that the proportion must be kept within a range that does not hinder the construction of the sprayed material.

[0013] Further, since the construction of the sprayed material in which the lightweight refractory aggregate is combined with the refractory aggregate has excellent heat insulating properties, it is inferior in corrosion resistance. Therefore, the lining material of the high-temperature furnace other than the molten metal container or the back of the lining is required. Is preferably used as a heat insulating material. The binder is alumina cement, magnesia cement, aluminum lactate, Portland cement or the like. The proportion is preferably 1 to 15 parts by weight with respect to 100 parts by weight of the refractory aggregate.

The organic fibers have the effect of improving the adhesion and drying properties of the spray material. Pulp fibers, plant fibers, animal fibers, synthetic fibers and the like can be used. Among them, a synthetic fiber that can be obtained stably is preferable. Specific examples of the synthetic fibers include polypropylene (including PVA), nylon, PVA, polyethylene, acrylic, polyester, pulp, and the like. The proportion of the additive is 0.1 to 100 parts by weight of the refractory aggregate.
It is preferably from 0.5 to 1 part by weight. If the amount is too small, the adhesiveness and the drying property are inferior.

The spraying material used in the present invention further contains gas-containing spherical hollow particles based on the above composition. The outer shell component of the gas-enclosed spherical hollow particles is, for example, a polymer of acrylonitrile and / or a copolymer having a high acrylonitrile content. Specific examples thereof include (meth) acrylate-based monomers and It is a copolymer obtained by copolymerizing a monomer, vinyl halide, vinylidene halide, vinyl acetate, butadiene, vinylpyridine, chloroprene and the like.

The polymer and / or copolymer may be used in combination with other comonomers or crosslinking agents (divinylbenzene, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, trimethylolpropane). Tri (meth) acrylate, 1,3 butylene glycol di (meth) acrylate, allyl (meth) acrylate, triacrylformal, triallyl isocyanurate, etc.).

The gas-containing spherical hollow particles are produced, for example, by heating the foam containing a foaming agent and expanding the foaming agent. At that time, as the blowing agent, for example, hydrocarbons such as n-pentane, isopentane, neopentane, butane, isobutane, hexane, petroleum ether, chlorinated hydrocarbons such as methyl chloride, methylene chloride, dichloroethylene, trichloroethane, and trichloroethylene;
Trichlorofluoromethane, dichlorofluoromethane,
Specific freons such as dichlorofluoroethane and dichloropentafluoropropane and alternative freons are exemplified, but not limited thereto.

The average particle diameter of the gas-containing spherical hollow particles is 5 μm.
If it is less than m, the effect of the present invention is not largely impaired, but the production of the spherical hollow particles containing the gas itself is unpreferable because of its extremely fine size, which increases the cost. 200μ on average
If it exceeds m, there is no effect on separation of the spray material and prevention of dripping. The particle diameter of the gas-containing spherical hollow particles can be measured by, for example, a microscopic method in which an image obtained by a stereoscopic microscope is analyzed by an image processing device.

The proportion of the gas-containing spherical hollow particles in the spray material is preferably 0.01 to 2 parts by weight in terms of solid content.
If it is less than 0.01 part by weight, the heat insulating effect is poor, and if it exceeds 2 parts by weight, the effect of preventing dripping when spraying material is applied is not remarkable probably due to excessive fluidity.

The gas-containing spherical hollow particles used in the present invention can be obtained from commercial products. For example, “Trademark: EXPANCEL (product code 5) of Nippon Philite Co., Ltd.
51DE, 551WE, 461DE, 091DE) and Matsumoto Yushi Seiyaku Co., Ltd. “trademark: Matsumoto Microsphere (product code F-30E, F-50E, etc.)” and the like.

Since the gas-containing spherical hollow particles are extremely lightweight, it is preferable that the surface thereof be wetted in advance with water or the like at the time of addition to the spray material composition in order to facilitate handling. In the above-mentioned addition ratio of the gas-containing spherical hollow particles, the solid component conversion means the weight excluding the water used in this wetting treatment.

The spraying material used in the present invention must have the above composition, but if necessary, dispersant, clay, bentonite, CMC, fly ash, ceramic fiber, metal fiber, surfactant, collector, water reducing agent Agent, metal powder (for example, A
l, Si or an alloy thereof), a foaming agent, an antioxidant, an antidigestion agent, a curing retarder, a curing accelerator, coarse refractory particles, and the like. Sawdust, synthetic resin pieces, foamed resin particles, and the like may be added as long as the effects of the present invention are not impaired.

For example, the dispersant has the effect of imparting fluidity to the spray material. Specific examples include inorganic silicates, carbonates, phosphates, organic polycarboxylates, polymers of carboxylic anhydrides, aromatic polycyclic condensate sulfonates, and melanin resin sulfonates. Lignin sulfonate, polyacrylate and the like. The preferable addition amount is 0.01 to 1 part by weight based on 100 parts by weight of the refractory aggregate.

In the present invention, the spraying material comprising the above-mentioned composition is kneaded by adding the working moisture in advance. The appropriate amount of the working water varies depending on the particle size composition of the refractory aggregate, the presence or absence of a dispersant, and the like, but is preferably in the range of 3 to 15 parts by weight when the entire spraying material composition is 100 parts by weight.

Next, the kneaded material is supplied to a nozzle by a squeeze type, screw type, piston type or the like pressure pump, and the nozzle is sprayed while adding a quick-setting agent. The quick-setting agent is preferably added by compressed air in the form of an aqueous solution in order to make it more uniformly mixed in the spray material. FIG. 1 schematically shows a spraying device used in the present invention. The nozzle (1) is connected to a quick-setting agent supply pipe (2), and the spray material supplied from the pressure-feeding nozzle (not shown) is added after the quick-setting agent is added together with the compressed air in the nozzle (1). , Wall surface (3). (4) is a construction body of the spray material.

[0026]

EXAMPLES Table 1 shows the quality of the lightweight refractory aggregate and the gas-containing spherical hollow particles used in each example. Tables 2 and 3 show the spray materials used in Examples of the present invention and Comparative Examples and the test results.

In the test, the distance from the tip of the nozzle to the surface to be sprayed was 500 mm with respect to the wall composed of irregular refractories.
In order to form a 200mm thick construction body.
0 kg was sprayed. At that time, the spray material was kneaded in advance with the amount of working water shown in the table, supplied to the nozzle by a piston type pressure pump, and sprayed at a discharge speed of 40 to 60 kg / min.

The quench hardener was an aqueous sodium silicate solution (water glass) adjusted to a concentration of 48 Baume and added to the spraying material together with auxiliary compressed air near the nozzle tip. The addition amount of the gas-containing spherical hollow particles shown in Tables 2 and 3 is a solid content converted value.

Fluidity: The sprayed material immediately after kneading was measured using a cone-shaped mold having an inner diameter of 100 mm at the lower end. The state where no flow occurs at all is 100 mm, and the larger the size, the better the flowability.

Adhesion: The degree of dripping during spraying was examined. Specific gravity separation degree: It was examined from the cross-sectional structure of the sprayed material construction. Tissue strength: After kneading the blended composition with a mixer, the cast body obtained by casting was heated and dried at 110 ° C. for 24 hours, and then the flexural strength was measured at room temperature.

Insulation: The thermal conductivity of the construction obtained in the same manner as described above was measured in accordance with JIS: R2618-79 (test method for thermal conductivity of refractory insulated brick by hot wire method).

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

[Table 3]

Table 2 shows the alumina-magnesia spray material, and Table 3 shows the chamotte spray material. According to the embodiment of the present invention, regarding the workability of the spray material and the physical properties of the construction body,
In each case, excellent results are obtained. In addition, some of the embodiments of the present invention also use a lightweight refractory aggregate. However, since the ratio of the lightweight refractory aggregate was relatively reduced, the fluidity and the specific gravity separation were not significantly affected. The effect of is not impaired.

In Table 2, Comparative Example 1, in which no gas-containing spherical hollow particles were added, was inferior in the heat insulating effect. Comparative Example 2 in which the particle diameter of the gas-containing spherical hollow particles is large is inferior in adhesion and less effective in preventing specific gravity separation. Comparative Example 3, in which fine alumina-silica spherical hollow particles were added, had no effect on the prevention of specific gravity separation. In Comparative Example 4 in which a large amount of organic short fibers were added, the fluidity was significantly reduced. In Comparative Example 4, there was concern about nozzle clogging, and a spraying experiment could not be performed.

In Table 3, Comparative Example 5 did not contain spherical hollow particles containing gas, and was inferior in heat insulation. Comparative Example 6, in which the particle diameter of the gas-containing spherical hollow particles is large, is inferior in adhesion and less effective in preventing specific gravity separation.

The construction method according to the present invention can be used for refractory lining, refractory coating or repair of various industrial kilns or associated equipment. Examples of industrial kilns and associated equipment include blast furnace gutters, converters, hot blast stoves, ladle, mixed iron wheels, mixed iron furnaces, converters, electric furnaces, vacuum degassing furnaces, tandems, gas injection lances, soaking Furnace,
Heating furnace, non-ferrous metal furnace, incinerator, chemical industrial furnace, incinerator, rotary kiln, boiler, cement industrial furnace, shaft kiln, etc.

When used for the lining of a molten metal container due to its heat insulating effect, it is also effective for the lining and the construction of the back layer.

[0040]

According to the construction method of the present invention, as described above, a heat-insulated sprayed construction body having a uniform structure can be obtained with excellent workability. Further, since the present invention is excellent in preventing dripping of the sprayed material, the construction can be efficiently performed in forming a construction body having a large thickness.

[Brief description of the drawings]

FIG. 1 schematically shows an example of a spraying apparatus used in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle 2 Quick setting agent supply pipe 3 Wall surface 4 Spray construction

Claims (4)

[Claims] 1. A refractory aggregate, a binder and organic short fibers,
A spraying material containing gas-containing spherical hollow particles made of a thermoplastic resin having an average particle diameter of 5 to 200 μm is supplied to a nozzle by a pressure pump after adding working water in advance, and a quick-setting agent is formed in the nozzle. A method of spraying refractories, characterized by adding and spraying. 2. The refractory spraying method according to claim 1, wherein the ratio of the gas-containing spherical hollow particles is 0.01 to 2 parts by weight in terms of solid content based on 100 parts by weight of the refractory aggregate. 3. The method according to claim 1, wherein a part of the refractory aggregate is made of a lightweight refractory aggregate. 4. A spraying material used in the refractory spraying method according to claim 1, 2 or 3.